Biologists, Sportsmen Outline Cormorant Control Plans
Meetings at St. Ignace, Les Cheneaux Call for Expanded Harassment Efforts
By Amy Polk

The double-crested cormorant population in the Les Cheneaux Islands will be reduced this year from 1,000 nesting pairs to 500 and harassment efforts will be expanded to deter cormorant feeding. Volunteers are being sought for the project.

The control program was outlined March 12 at the Les Cheneaux Sportsman’s Club in Cedarville by Department of Natural Resources (DNR) fisheries biologists and United States Department of Agriculture (USDA) Wildlife Services Agent Tony Aderman.

A few in the audience said they still would like to see cormorant populations wiped out, but Mr. Aderman said total elimination of the bird is not the objective of the cormorant control project. Lethal control and harassment projects were designed to keep the bird’s population in check to allow recovery of fish populations. So far, it seems to be working in the Les Cheneaux Islands, where yellow perch populations have bounced back since the start of the cormorant control project there.

“The Fish and Wildlife Service isn’t going to let us take it down to zero,” Mr. Aderman said. “It just isn’t going to happen. We may get a maintenance program at some point.”

During an annual report on the cormorant control project, Mr. Aderman reminded the public that a hard-won permit to kill cormorants is still vulnerable, and will expire or be extended in 2009. At that time the standing depredation order can be extended or revoked, but he noted, “Things look pretty good for extending it, as far as I know.”

The Fish and Wildlife Service, which manages all migratory birds, including double-crested cormorants, relaxed strict protection of the bird in 2003, issuing a list of rules governing how the bird can be managed in the United States. Michigan is one of 24 states where lethal methods to control cormorants is allowed.

Since that time, Wildlife Services received permission to kill and harass cormorants to knock down the large populations that nest in the area and feed on local fish. Agents oil the eggs of nesting adults during the summer breeding season and shoot a designated number of adult birds throughout the season. Egg oiling will take place over a period of 18 to 20 days from May to late July, Mr. Aderman said. Agents will continue limited shooting, aerial surveys, telemetry, and monitoring this summer.

Anglers have suspected for years that cormorants are a part of declining perch populations, Mr. Aderman said, but it took compelling evidence from DNR fisheries research to make a case for control in the Les Cheneaux Islands.

“We wouldn’t have a leg to stand on if it weren’t for the DNR Fisheries’ research,” he said of Dave Fielder’s study on yellow perch populations. “The DNR Fisheries Division helps set management priorities for different locations. Otherwise we had no scientific evidence to base our control project on.”

Dave Fielder, research biologist at the DNR’s Alpena Fisheries Research Station, has collected seven years of population data on yellow perch populations that laid the scientific foundation of the case for cormorant control in the Les Cheneaux Islands. His work showed that perch numbers dropped steadily with the growing presence of cormorants in the area, until perch numbers virtually bottomed-out in 2000.

“In Hessel Bay in 2000, we couldn’t find one perch,” Mr. Fielder said, adding that perch have now been found there every year after cormorant control started.

The Fish and Wildlife Service authorized local control by approved state, tribal, and federal agents in 2003 in areas where cormorants were proved to be causing damage. The Les Cheneaux Islands project was one of the first approved under the depredation order, and Wildlife Services began control activities in Les Cheneaux and Drummond Island in 2004. At that time, agents started work on an estimated 5,500 cormorant nests. Four years later, agents have reduced the number of nesting pairs to 1,000.

Agents have been working on island cormorant rookeries at Saddlebag Island near DeTour, Crow Island in the East Entrance of Cedarville, Goose and the St. Martin islands near Hessel, and Green Island west of the Mackinac Bridge near St. Ignace.

Mr. Aderman compared the number of nests at the five targeted rookeries in 2003 to the latest nest numbers in 2007. At Saddlebag Island, nest numbers have been reduced from 646 in 2003 to 265 in 2007. Crow Island nests have been reduced from 211 to 2, Goose Island numbers have been reduced from 1,876 to 0, St. Martin islands nests have been reduced from 2,539 to 554.

At Green Island, where control did not start until 2006, nest numbers increased from 224 o 617.

Mr. Aderman said the Goose Island reduction is so dramatic because someone let raccoons loose on the island. The raccoons not only wreaked havoc on the nests, they probably drove the birds off to other rookeries. Other bird species, including black crowned night herons, green herons, and gulls were driven away, too. Similar activities took place on an island in Bay de Noc, where someone released pigs. Mr. Aderman and Mr. Fielder repeated a warning against such unauthorized and destructive control tactics.

“Please resist the temptation to take control into your own hands,” Mr. Fielder told the audience. “Vigilante actions like these play right into the hands of critics” of the cormorant control project.

Not everyone approves of killing cormorants, and Mr. Aderman reminded the audience of a pending lawsuit brought against the Fish and Wildlife Service by animal rights groups who oppose lethal and harassment tactics authorized by the service. Abusing the right to control cormorant populations puts the depredation order at risk, he said.

Since the first rogue raccoon activity, however, the Les Cheneaux cormorant control project has operated smoothly, and Mr. Aderman complimented the cooperation between the DNR, community groups, local volunteers, and agents. Such cooperation is good, he said, because the Les Cheneaux Islands control project is being watched by policy makers and biologists around the country. If it works, it may be a model for future projects.

Michigan United Conservation Clubs and state legislators have also successfully lobbied for state and federal funding for control projects in Michigan, and the state has the largest control project in the United States, Mr. Aderman said.

State and federal agencies will be challenged in the upcoming years to determine the balance between double crested cormorants and the fisheries. Social and economic factors and changes in the Great Lakes all influence the bird’s existence. Answering a question from the audience about why cormorants were introduced to the Great Lakes, Mr. Fielder said the bird is native, and its existence has been documented as far back as the 1800s. Use of the pesticide DDT nearly eliminated cormorants and other Great Lakes waterfowl until it was banned in 1972. Cormorant populations have been rising ever since, owing mostly to the proliferation of the invasive alewife, a forage fish.

“Cormorants just didn’t exist in such quantities as they do now,” Mr. Fielder said, but “the fish communities of the Great Lakes had changed to favor fish eating birds like the cormorants.”

Now alewives have nearly disappeared in Lake Huron, and cormorants have turned to other fish, primarily sticklebacks, according an analysis of cormorant stomach contents. Mr. Fielder reported the results of the 2005 and 2006 analyses, which showed the growing presence of round gobies, another invasive fish species, in the cormorant diet.

“Cormorants are still taking more yellow perch than the anglers are, despite the relatively tiny number of perch they are taking,” he said.

According to his research, cormorants consume 87% of the total number of yellow perch removed from the population, while anglers take an estimated 13%.

“It used to be 99% cormorants and 1% anglers,” Mr. Fielder said.

His 2007 fisheries report, based on the annual April-through- October creel census and the annual October netting survey, show anglers are still not fishing as much as they did in the 1980s, when perch harvest reached an all-time high of 400,000. This diminished effort might be why anglers are taking fewer perch, he said.

Yellow perch populations seem to have stabilized since an explosive recovery in 2005 and 2006, and he wonders if the Les Cheneaux Islands will ever have as many perch as there were in the 1980s.

“It appears yellow perch abundance has leveled off a bit, and I expect it to bounce around a bit,” Mr. Fielder said.

A suggestion to close certain bays to fishing during the spring perch spawning season was discouraged by DNR biologists, Mr. Fielder and Dave Borgeson of the Northern Lake Huron Management office in Gaylord.

Mr. Fielder said a move to close the bays to fishing would be intended to address a reproduction problem, but reproduction in the Les Cheneaux Islands is good.

“We’re getting good reproduction and recruitment here,” he added. “Saving a few eggs in the spring is not going to help.”

In fact, Cedarville High School has reported some of the highest numbers of perch egg skeins in 2006 and 2007 student surveys, which demonstrates good egg production.

Mr. Fielder said the bays would have to be closed in the middle of the summer to have the best results, and the DNR is reluctant to recommend closing bays during the popular summer recreational fishing season.

“All along, we’ve wanted to avoid putting the pressure on the backs of anglers,” Mr. Borgeson added.

Other cormorant harassment and control efforts are taking place in Michigan at Bay de Noc, South Manitou Island, Beaver Island, Ludington, Thunder Bay, Indian Lake, South Manistique Lake, Manistique Lake, Brevort Lake, Drummond Island, Grand Lake, Alpena, Long Lake, and Au Sable.

Mr. Aderman said harassment efforts on Brevort Lake have been effective, and volunteers there managed to scare cormorants away more than 90% of the times they try to feed on fish. He said the high success rate is the result of an intensive and time-consuming effort.

To volunteer for the cormorant harassment project, call Tony Aderman at the USDA Wildlife Services office in Gaylord at (989) 705-8467, or e-mail him at tony.aderman@aphis.usda.gov.